1. Field of the Invention
The present invention relates to a disc brake assembly for wheeled vehicles, and more particularly to a disc brake assembly which decreases weight of the assembly without decreasing the hardness of the caliper member and which decreases generation of brake equal.
2. Description of the Prior Art
In a disk brake, it is known that an unpleasant noise, termed squeal, is sometimes generated when the disc brake is applied. It is thought that the squeal is caused by minute vibrations of the brake pads which are generated by friction forces when the brake pads are pressed against the rotating brake disc.
On both sides of the brake pad, the direction of rotation of the disc defines the leading side and the trailing side. The leading side of the brake pads is with reference to the direction of rotation of the disc as it passes through the caliper and brake pad assembly and is the forwardmost location, viewed in the direction of disc rotation, of the brake pad assembly. Conversely, the trailing side is the rearmost location, viewed in the direction of disc rotation, of the brake pad assembly.
Brake torque is created when the brake pads are applied to the disc. In the prior art, this brake torque is transmitted to the end portion of the leading side of each brake pad. Namely, the end portion of the leading side of each brake pad contacts a fixed member and the brake torque is transmitted to the fixed member at the leading side. The conventional disc brake assembly of this kind is disclosed, for example, in Japanese application publication No. 50-7701 published on Mar. 28, 1975, or in Japanese application laid-open publication No. 55-47022 published without examination on Apr. 2, 1980. In each disc brake, the brake torque is transmitted at the leading side.
In the conventional disc brake assembly, however, since the brake torque is transmitted at the leading side, a reaction force is generated in the fixed member against the pressing force of the brake pad of the leading side. As a result, the reaction force and the friction force between each brake pad and the disc generates a force moment in the brake pad. This moment generates partial abrasion in the brake pad, thereby generating brake squeal.
Further, in the disc brake, if the hardness of the caliper member is low, the flexure of the caliper member is large. As a result, the consumption of brake fluid increase and pedal feel during brake operation deteriorates. This problem may be overcome by increasing the thickness of the caliper member, however, the weight of the disc brake will increase.